View Full Version : Raycast from MEL Script
07-09-2012, 11:02 AM
I'm writing a procedural content script based on something I'm working on in Unity (C#). However it requires the ability to do a simple raycast hit test against geometry in the scene. I need to be able to pass a start point, a direction, and have a boolean return true if geometry was hit by the ray.
Is there a built-in Raycast function? I couldn't find anything in the command reference, and I'm not really sure where to start looking into rolling my own.
Some tips on where to start would be greatly appreciated!
07-09-2012, 11:30 AM
See if this helps:
and if you reached the same conclusion then consider this:
Although in your case I think it might be an overkill, and you might be satisfied with intersection of the objects bounding boxes.
Also for your case I would look into the selection interface, which tells if a click selected an object. You might be able to employ this mechanism to shoot a ray from an arbitrary point.
07-09-2012, 12:43 PM
you could also start by doing a search on this forum. search for rayIntersect.
07-09-2012, 12:47 PM
Brilliant, thank you very much!
EDIT: Both of you! Thanks :) I found a couple of threads mentioning "raycast" but not enough to kickstart from.
07-10-2012, 06:08 PM
I've played around with the python code from the first link, and it works perfectly but only if I have a positive ray direction, and in many cases a positive ray origin.
If I create a unit sphere (radius=0.5), set the ray origin at [0,0,0] and the ray direction to [0,1,0], the script returns 1 indicating a ray hit.
If I set any negative values in the ray origin or the ray direction, it gets a bit flakey and doesn't produce expected results (assuming I'm expecting the right results...)
For example, setting the ray origin at [0,1,0] and the ray direction to [0,-1,0], the script returns 0.
07-10-2012, 11:42 PM
First I would appreciate if you don't invent new definitions. Unit sphere means radius=1 (wiki).
Second, you have this line:
result = int(fmod(len(hitFaces), 2))
which I assume means return the modulus of the number of faces that were hit and 2. Meaning odd return true, even return false. Sounds familiar? Right, this script checks if a point is inside a mesh. I think that something such as
result = hitFaces
would get you what you want. But I'm only guessing, so let me know if you want me to actually check this.
07-11-2012, 01:26 AM
Thanks for pointing out the modulus. That was the problem.
07-11-2012, 01:26 AM
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